Various methods are being explored to allow characterization and subsequent identification of widely differing microbial biotypes. The aim is to have standard methods which allow comparison of fundamental properties of microorganisms to find broad commonalities. Simplicity of assessment is a second goal. Nutritional requirements in defined media, DNA per cell, protein per cell, DNA to protein ratio, ultraviolet and visible spectra, selected enzyme levels, guanosine - cytosine content, and logically similar tests are being evaluated.